This invention relates to the manufacture of pneumatic tires and more particularly to a device for supporting an unvulcanized pneumatic tire.
In the manufacture of pneumatic tires the various components of the tire including various reinforcing components embedded in a matrix of unvulcanized rubber or other unvulcanized rubberlike material are assembled on a building form. The tire at this stage of manufacture comprises what is generally referred to as an unvulcanized tire carcass. For purposes of simplicity an unvulcanized tire carcass will be referred to hereinafter as a carcass. The carcass is then transferred to a shaping and vulcanizing press in which it is shaped to the final form and vulcanized. The unvulcanized tire, therefore, must be transported and stored for some period of time.
The present invention relates to the transportation and storage of carcasses between the building and vulcanizing stages. The carcass generally does not have enough strength or rigidity to maintain the shape in which it was built on the building form. Such carcasses, therefore, have a tendency to sag or droop under their own weight and become distorted. A distorted carcass can result in non-uniformities in the tire when it is shaped and vulcanized in a press.
This problem is more acute with respect to the socalled drum built or pulley band radial ply tires. These radial tires are characterized by the fact that they are completely built in a generally cylindrical configuration and only brought to the torus or tire shape in the curing press. Such a tire is disclosed in U.S. Pat. No. 3,409,492. These tires generally have even less rigidity in the unvulcanized state than do bias or bias belted tires, and, therefore, have a greater tendency to lose their shape due to sagging or drooping under their own weight during the transportation and storage process.